1. Field of the Invention
The present invention relates to a photographing system of a television camera or a video camera in which an image pickup means such as a vidicon type tube, a CCD or the like is used and, particularly, it relates to a photographing system of this kind in which use is made of a shutter which is arranged to provide intermittent exposures.
2. Description of the Related Art
In a photographing system such as a television camera or a video camera, in which an image pickup plane is scanned by a scanning beam, (which will be generally referred to as "television camera"), it has been a usual practice to use means for intermittently exposing the image pickup plane when it is desired to take a picture of an object moving at a high speed faster than the scanning time of one frame. By using such intermittent exposure means, it is possible to apply the exposure to the image pickup plane at a high shutter speed substantially faster than the scanning time per one frame, so that a distinct picture may be obtained, without causing blurring of picture owing to the movement of the object.
In an example of the conventional arrangement of this kind, a shutter of a rotary disc type having a transparent portion therein is used. This shutter is arranged in front of a photographing lens and it is rotated to intermittently pass a bundle of rays coming from the object into the photographing lens at short periods. According to such arrangement, a spatial restriction required to dispose the shutter means is small, but the rotary shutter requires a relatively large diamater in order to allow the bundle of rays having a relatively large diameter to pass into the photographing lens, with the result that the overall size of the device is increased.
In another example of the conventional arrangement of this kind, a rotary shutter is disposed at a position near an image forming plane of a photographing lens to intermittently pass a bundle of rays, and the photographing lens and the shutter are formed as an integral system. According to this arrangement, the shutter means including the rotary shutter and the mechanism for driving said rotary shutter is relatively small in size, but it is very difficult to dispose such shutter means at or near the position of the image pickup plane, in view of a mechanism of the adapter. Furthermore, the adapter of this type is provided with a bulit-in shutter, so that it is relatively large in size, and such an arrangement is unsuitable to a simple photographing operation which does not require the use of the built-in shutter.
With the object of eliminating the above-mentioned disadvantages of the conventional arrangements, we have proposed a detachable adapter which is used at the time of taking a photograph of an object moving at a high speed, as disclosed in our co-pending U.S. patent application, Ser. No. 692,129. According to this proposal, a first optical system constitutes a master lens and an adapter including a second optical system is detachably attached to said first optical system. At the time of ordinary photographing operation, only the first optical system is used, while at the time of taking a photograph of a high-speed moving object an intermediate image of the object is formed by the first optical system and then said intermediate image is transformed by the second optical system included in the adapter into a reformed image on an image pickup means. A rotary shutter is disposed near the position where the intermediate image is formed. According to this arrangement, the image formed on the image pickup plane when the adapter including the second optical system and the rotary shutter is used to take a photograph of a high-speed moving object is in reversed relation to the image formed on the image pickup plane at the time of ordinary photographing in which only the first optical system is used to take a photograph of the high-speed moving object, it is necessary to take a special measure, such as mounting the camera body in reversed position, electrically reversing the scanning direction of the photographing means, etc.